Ten healthy volunteers were imaged with breath-hold, three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) using single-variable-angle uniform signal excitation (VUSE), double-VUSE, and flat radiofrequency (RF) pulses with various doses of contrast agent. The ability of each technique to display pulmonary vasculature was evaluated. Images were segmented to isolate lungs, and maximum intensity projections (MIPs) were computed. All MIPs were assigned an image quality (IQ) rating, and signal-to-noise ratios (SNRs) were measured in pulmonary vessels. Without contrast agent, subsegmental vessels were displayed in single- and double-VUSE images while no vessels were visible in flat images. With equal doses of contrast agent, SNRs and IQ ratings were comparable for images obtained with VUSE and flat pulses. In addition, single-VUSE pulses produced more uniform signal from vessels than flat pulses in contrast-enhanced images. The results indicate that non-contrast-enhanced 3D TOF pulmonary MRA with VUSE RF pulses may be a useful screening tool. In addition, contrast-enhanced 3D TOF MRA with VUSE pulses may be useful as a stand-alone technique for assessing the pulmonary vasculature or as an adjunct to contrast-enhanced 3D TOF MRA with flat pulses. J. Magn. Reson. Imaging 10:929-938, 1999.
Copyright 1999 Wiley-Liss, Inc.